Glutaminyl-tRNA synthetase generates Gln-tRNA (Gln) 10 (7) - fold more efficiently than Glu-tRNA (Gln) and requires tRNA to synthesize the activated aminoacyl adenylate in the first step of the reaction.

This hydrolysis of glutaminyl adenylate represents a novel reaction that is directly analogous to the pre-transfer editing hydrolysis of noncognate aminoacyl adenylates by editing synthetases such as isoleucyl-tRNA synthetase.